Bone and tissue resection devices and methods

ABSTRACT

Embodiments of devices for converting continuous rotational motion into oscillating motion are disclosed herein. In one embodiment, an oscillation device can include an input shaft that rotates about a first axis, a portion of the input shaft defining an eccentric section that defines a second central axis offset from the first axis, a connector rotatably coupled around the eccentric section, an oscillating shaft offset from the input shaft that rotates about a third axis, and a pin coupled to the oscillating shaft and extending towards the connector. The connector includes a sleeve slidably receiving an end of the pin, and continuous rotation of the input shaft about the first axis causes an eccentric movement of the connector, and the eccentric movement of the connector oscillates the sleeve along the pin and oscillates the pin with respect to the oscillating shaft, thereby oscillating the oscillating shaft about the third axis.

FIELD

The present disclosure relates to systems, devices, and methods forresecting soft tissue or bone, and more particularly relates to suchdevices that can aid a user in resecting soft tissue in constrainedenvironments, such as during minimally-invasive surgical procedures.

BACKGROUND

Various surgical procedures involve the removal or manipulation oftissue at a surgical site. For example, in spinal surgeries there isoften a need to remove tissue, including bone, to achieve goals such asincreasing or providing access to another site (e.g., an intervertebralspace), relieving pressure on nerves, etc. A number of instruments existto perform these tasks, but often have various shortcomings. Forexample, poor instrument ergonomics can lead to musculoskeletaldisorders, surgeon fatigue and stress, and reduced accuracy. In somecases the devices can be manually operated, and therefore slow tocomplete the task while requiring high levels of muscle activation fromthe surgeon or other user. Whether manually actuated or not, slowoverall resection rates can also be caused by the need for multipleinstrument passes and repeated cleaning of tissue from the instrument.Still further, inaccurate removal can result from the instrument movingrelative to the tissue being resected or manipulated, a factor that canalso result in additional instrument passes or actuations beingrequired.

There is also a potential to damage sensitive nerves and vessels withmany prior devices due to movement of a cutting tool relative to softtissue (e.g., a rotating blade) and the exposure of these tissues to theblade itself. With some devices, resected tissue can be pulverized orotherwise destroyed by a device, such that removal of the tissue moredifficult and/or inspection of removed tissue is impossible. A furtherdrawback of prior devices is that the surgeon's view of the bone ortissue being resected or manipulated can be obstructed by the toolitself, which can lead to unintentional iatrogenic trauma.

If a path is being cleared to make way for an implant or anotherinstrument, then a constant cross section through cut is necessary.Current instruments such as a burr that perform resection tasks withoutmaking a straight cut like an osteotome run the risk of resecting eithertoo much or too little bone in these circumstances.

Devices such as a burr that grind or otherwise convert targeted tissueto smaller sized particulate or slurry can damage the targeted tissuereducing the ability for it to be used as autograft in other aspects ofthe procedure.

Moreover, spine and other surgical procedures are increasingly performedusing minimally invasive surgical (MIS) and/or microsurgical techniques,which can have a number of advantages, including reduced risk of patientinjury, faster recovery time, etc. Such procedures are typicallyperformed using various access ports or retractors that provide apassageway from the skin surface to the spine and intervertebral discspace. These ports and retractors often provide passageways of minimalsize, perhaps about 30 mm in diameter or less, in order to minimizetissue trauma and successfully traverse narrow anatomical passages.While these procedures provide a number of benefits, they can increasethe difficulty of performing various tissue resection or manipulationoperations, as the surgical site is accessed through these narrow portsor retractors. The above-noted drawbacks of prior tissue resection ormanipulation tools can therefore be exacerbated in minimally invasive ormicrosurgical procedures.

Accordingly, there is a need for improved devices and methods forperforming bone and tissue resection or manipulation.

SUMMARY

Certain aspects of the present disclosure provide for devices andmethods for resecting or manipulating bone and tissue that utilizepowered cutting systems with an oscillating or continuously rotatingblade, or an axially oscillating blade, to manipulate the border oftargeted tissue. The blade can either be exposed or within a housingthat can aid in preventing unintentional tissue resection. Aspects ofthe present disclosure include the mechanics of achieving saidoscillating or continuous rotation, or axial oscillation, as well asvarious forms of user interface or ergonomics, activation methods for apowered cutting system, cut shapes made by the tool, features tonavigate the tool to or within a surgical site, features to visualizethe cut tissue, and features to provide monitoring feedback, amongothers.

Embodiments of the present disclosure can include a powered cuttingsystem using a crescentic blade that cuts tissue or bone by oscillatingwithout spinning through a complete rotation and being translated intothe bone or tissue against a footplate. The oscillating blade canprevent or reduce nerve damage by avoiding excessive tangling of nervetissue due to a small angular displacement oscillation and limiting themagnitude of the strain to the soft tissue. Additionally, high frequencyoscillations can enable the blade to slice bone with less force anddamage, as opposed to hydraulic or pneumatic systems for crushing ofbone, which require large amounts of force, or burr systems thatobliterate bone and can entangle and damage nerve tissue with thespinning burr.

Embodiments of the present disclosure can include a powered cuttingsystem using a cylindrical blade that features a shroud to protecttissue that is not targeted from resection from the cutting element.

Certain embodiments of the present disclosure can include a mechanicaltransmission or oscillator that converts the rotation of a motor intooscillation. In one embodiment, the oscillator can use a linear sleeveand piston arrangement to provide blade oscillation rates of at leastabout 80,000 oscillations per minute. Other embodiments can include afour-bar linkage oscillator to achieve different ranges of oscillationrate and oscillation angle. Both oscillator systems can provideimprovements over prior mechanisms, such as a Scotch yolk, which are notsuited to high rates of oscillation as described herein. Certainembodiments of the oscillator can also include a torsional harmonicdamper to separate oscillation from a motor.

Certain embodiments of the present disclosure include a cutting assemblycomprising a footplate and crescentic blade configured to extenddistally from a sleeve to the footplate. In some embodiments, thecrescentic blade can enable a smaller form factor of the cuttingassembly. Additionally, in some embodiments, the footplate can beattached to the sleeve with one or more support members that allow theblade to be viewed from either the top or bottom as it passes though thecutting region. In some embodiments, the blade can extend from a slot inthe distal end of the sleeve such that, when retracted, the blade can becleaned of debris as it passes though the slot.

Example embodiments of the present disclosure include a bone and tissueresection device including a blade having a distal cutting edgeconfigured to perform a cutting action that produces a plug or core froma media being cut by the cutting edge, a drive mechanism arranged totransfer an oscillating force to the cutting edge for oscillating thecutting edge, a shield positioned to block contact with a portion of thecutting edge, and a depth adjustment mechanism configured to translatethe cutting edge along a proximal-distal axis of the shield to adjust anaxial position of the cutting edge relative to the shield. The drivemechanism can include a four bar linkage oscillator that convertsrotation from a motor coupled to the drive mechanism into theoscillating force. The drive mechanism can include a motor that rotatesin opposite directions to produce the oscillating force. The drivemechanism can include a scotch yoke mechanism. The drive mechanism caninclude an eccentric shaft having an offset bearing coupled with alinear bearing to generate the oscillating force, wherein the linearbearing is coupled to the cutting edge. The drive mechanism can producean oscillating axial motion of the cutting edge along a proximal-distalaxis of the cutting edge.

The drive mechanism can include a cam mechanism configured to producethe oscillating axial motion of the cutting edge. The drive mechanismcan include a piezoelectric mechanism configured to produce theoscillating axial motion of the cutting edge. The oscillating force cancause oscillation of the cutting edge around a proximal-distal axis ofthe cutting edge. In some embodiments, the oscillating force causesoscillation of the cutting edge around a proximal-distal axis of thecutting edge, and wherein the drive mechanism is configured to producean oscillating axial motion of the cutting edge along theproximal-distal axis of the cutting edge while the cutting edgeoscillates around the proximal-distal axis of the cutting edge.

The cutting edge can define a crescentic shape such that the plug orcore of the media being cut can be extracted through an open side of theblade. The cutting edge can define a shape matching an implant, suchthat the plug or core cut from a media clears a path for implantation ofthe implant in the media.

The shield can include a closed distal end configured to prevent contactwith the cutting edge. In some embodiments, the shield includes an opendistal end configured to enable the blade to be inserted from the distalend into drive mechanism. The shield can define one or more openingslocated radially from the cutting edge to expose the cutting edge.

In some embodiments, the cutting edge defines a crescent shape and theblade defines and concave surface and a convex surface opposite theconcave surface, and the shield defines an opening radial to the convexsurface of the blade and closed region radial to the concave surface,such that the opening of the shield enable a user to view the blade andthe closed region contains media resected by the cutting edge.

In some embodiments, the cutting edge defines a crescent shape and theblade defines and concave surface and a convex surface opposite theconcave surface, and the shield defines a first opening radial to theconvex surface of the blade and a second opening radial to the concavesurface of the blade, and the shield defines one or more posts separatethe two openings, the one or more posts extending to a distal end of theshield. In some embodiments, the shield includes a protrusion extendingtowards the concave surface of the blade for extracting material fromthe concave surface the blade when the blade is translated in a proximaldirection by the depth adjustment mechanism after be driven distally tocut the material. The depth adjustment mechanism can be configured toadjust the axial position of the cutting edge with respect to the shieldwithout adjusting the axial position of the drive mechanism with respectto the shield. The depth adjustment mechanism can be configured toadjust the position of the cutting edge by translating the drivemechanism along the proximal-distal axis of the shield.

In some embodiments, the bone and tissue resection device includes ahandle, and the depth adjustment mechanism is configured to be operatedby a user via the handle, such that, when a user applies a force to thehandle, the depth adjustment mechanism transfers the force from thehandle to the blade to adjust the position of the cutting edge. Thedepth adjustment mechanism can include a powered mechanism operable by auser to adjust the position of the cutting edge relative to the shield.

In some embodiments, the drive mechanism includes an input shaftconfigured to continuously rotate about a first central axis, a portionof a length of the input shaft defining an eccentric section, theeccentric section defining a second central axis that is offset from thefirst central axis, a linkage disposed around the eccentric section at afirst end thereof and having a lumen formed in a second end thereof thatis parallel to and offset from the second central axis, a pin disposedwithin the lumen of the linkage, and an oscillating shaft coupled to andoffset from the pin. Where continuous rotation of the input shaft aboutthe first central axis creates an oscillating movement of theoscillating shaft. In some embodiments, the blade is coupled to theoscillating shaft. In some embodiments, the input shaft furthercomprises a counter weight to balance to rotation of the eccentricsection about the first central axis.

In some embodiments, the bone and tissue resection device includes abearing disposed around the input shaft. In some embodiments, the boneand tissue resection device includes a bearing disposed around theoscillating shaft. In some embodiments, the bone and tissue resectiondevice includes a collet formed at a distal end of the oscillatingshaft, the collet including a plurality of arms extending distallyaround a central axis of the oscillating shaft.

In some embodiments, the shield is configured to detect nerves within apath of the cutting edge using electromyography (EMG) ormechanomyography (MMG). In some embodiments, the shield is able to benavigated to enable alignment of a cut area of the cutting edge.

Another example embodiment is a bone and tissue resection deviceincluding a stationary assembly with a housing, an elongated sleeveextending distally from the housing, and a cutting region disposeddistal to the sleeve, and a drive assembly including a blade shaftextending through the elongated sleeve, the blade shaft having a distaltip with a blade, wherein a cutting edge of the blade is configured toextend into the cutting region when the drive assembly advances distallyrelative to the stationary assembly, and a drive mechanism coupled tothe blade shaft and configured to engage with a source of continuousrotational motion, the drive mechanism configured to convert thecontinuous rotational motion into oscillating motion of the drive shaft.Where the drive assembly is configured to slidably couple to thestationary assembly to permit selective proximal and distal translationof the drive assembly relative to the stationary assembly by the depthadjustment mechanism. The blade can be sized to span the depth of thecut-out of the elongated sleeve. In some embodiments, the stationaryassembly includes a handle coupled to the housing, and the driveassembly includes a trigger configured to receive a force to move thedrive assembly relative to the stationary assembly. The trigger can bepositioned distal to the handle. The trigger can be positioned proximalto the handle.

The stationary assembly can include a handle coupled to the housing, anda trigger assembly configured to move with respect to the handle, thetrigger assembly configured to receive a force to move the triggerassembly and transfer the force to the drive assembly to move the driveassembly. In some embodiments, the stationary assembly includes a linearactuator configured to deliver linear motion to the drive assembly, andwherein the trigger assembly is operatively coupled with the linearactuator. In some embodiments, the linear actuator is a rack and pinionsystem comprising a first rack configured to be moved by the triggerassembly and a second rack configured to move the drive assembly. Insome embodiments, drive assembly comprises the second rack of the rackand pinion system.

The bone and tissue resection device of claim 8, wherein the rack andpinion system comprises a pinion assembly having first and secondbeveled pinions disposed along a common axis of rotation, wherein thefirst and second beveled pinions are biased towards each along thecommon axis of rotation by one or more biasing elements. In someembodiments, the trigger assembly comprises an actuation lever and atrigger, the actuation lever is configured to engage with the driveassembly and translate the drive assembly distally when the trigger ismoved towards the handle. In some embodiments, the trigger assembly isconfigured to rotate about an axis perpendicular to a longitudinal axisof the stationary assembly.

In some embodiments, the handle extends along a longitudinal axis of thestationary assembly, and the trigger assembly is configured to translatealong an axis perpendicular to the longitudinal axis of the stationaryassembly.

In some embodiments, the drive assembly includes a housing having one ormore mating features, the housing of the stationary assembly includesone or more corresponding mating features, and the corresponding matingfeatures of the stationary assembly are arranged to be removably coupledwith the mating features of the drive assembly and, when coupled, retainthe drive assembly to the stationary assembly. In some embodiments, thecorresponding mating features of the stationary assembly are configuredto slidably couple to the mating features of the drive assembly suchthat the drive assembly is able to translate proximally and distallyalong a longitudinal axis of the stationary assembly. In someembodiments, the corresponding mating features of the stationaryassembly include one or more guide rails, and the mating features of thedrive assembly include one or more protrusions sized and shaped totravel along the guide rails.

In some embodiments, the drive assembly comprises a coupling configuredto be mechanically connected with a motor providing the continuousrotational motion, the coupling configured to transfer rotational energyfrom the motor to the drive mechanism.

In some embodiments, the elongated sleeve is removably coupled to thestationary assembly.

The bone and tissue resection device can include a biasing elementconfigured to bias the drive assembly proximally with relative to thestationary assembly. The bone and tissue resection device can include apowered actuator configured to move the drive assembly relative to thestationary assembly. In some embodiments, the powered actuator is any ofelectric, pneumatic, or hydraulic. In some embodiments, the deviceincludes a trigger operatively coupled with the powered actuator andconfigured to control movement of the drive assembly using the poweredactuator.

In some embodiments, the elongated sleeve comprises an electromyography(EMG) or mechanomyography (MMG) sensor configured to detect nerveswithin the cutting region. In some embodiments, the elongated sleeve isable to be navigated to align the cutting region.

Yet another example embodiment of the present disclosure is a cuttingassembly for a bone and tissue resection device, including a blade shafthaving a distal end with an arcuate blade, a sleeve surrounding theblade shaft and arcuate blade, the sleeve having a distal end definingan opening sized and shaped to allow the arcuate blade to translatedistally beyond the distal end of the sleeve, a footplate positionedbeyond the distal end of the sleeve and configured to resist distalmovement of material being cut by the arcuate blade when the arcuateblade is translated distally against the material, and a supportextending from the distal end of the sleeve to the footplate, thesupport element defining a cutting region between the distal end thesleeve and the footplate. The arcuate blade can be configured tooscillate about a longitudinal axis of the blade shaft. The arcuateblade can be a crescentic blade. In some embodiments, the distal end ofthe sleeve is partially closed and comprises a crescentic openingconfigured to allow the crescentic blade to pass through the crescenticopening. In some embodiments, the cutting region is further defined by apath of the exposed arcuate blade along the support when the arcuateblade is translated beyond the distal end of the sleeve towards thefootplate. In some embodiments, the footplate defines an outer edge thatextends radially beyond an outer edge of the arcuate blade. In someembodiments, the footplate defines an arcuate lip along the outer edgethat extends towards the arcuate blade. In some embodiments, thefootplate defines an arcuate trough formed in a proximal-facing surfaceof the footplate, where an outer edge of the trough is defined by thearcuate lip, and the arcuate trough is configured to receive the arcuateblade.

The support can include first and second beams extending distally fromthe sleeve to the footplate. In some embodiments, the arcuate blade isconfigured to translate between the first and second beams. The supportcan be configured to allow the arcuate blade to pass along an outside ofthe support beam as the arcuate blade is translated distally towards thefootplate. The blade shaft can be configured to be removably coupled toa drive mechanism of the bone and tissue resection device. In someembodiments, the sleeve is configured to be removably coupled to astationary component of the bone and tissue resection device at aproximal end thereof. In some embodiments, the sleeve defines anelongated tubular structure having an inner diameter sized to accept anouter diameter of the arcuate blade.

In some embodiments, at least one of the sleeve, the footplate, and thesupport includes a stop configured to contact any of the arcuate bladeand the blade shaft to prevent the arcuate blade from contacting thefootplate. In some embodiments, the footplate has a distal opening sizedto allow the blade to be inserted from the distal end. In someembodiments, the footplate, sleeve, and support are formed in a tubularstructure having one or more openings to expose tissue to a blade indesired directions allowing the blade to only cut material exposedthrough the openings.

Still another example embodiment of the present disclosure is anoscillator for converting continuous rotational motion into oscillatingmotion. The oscillator includes an input shaft configured tocontinuously rotate about a first central axis, a portion of a length ofthe input shaft defining an eccentric section, the eccentric sectiondefining a second central axis that is offset from the first centralaxis, a connector rotatably coupled around the eccentric section, anoscillating shaft offset from the input shaft and configured to rotateabout a third central axis, and a pin coupled to the oscillating shaftand extending towards the connector. Where the connector comprises asleeve slidably receiving an end of the pin, and continuous rotation ofthe input shaft about the first central axis causes an eccentricmovement of the connector, and the eccentric movement of the connectoroscillates the sleeve along the pin and oscillates the pin with respectto the oscillating shaft, thereby oscillating the oscillating shaftabout the third central axis.

The pin and sleeve can extend perpendicular to the axis of the eccentricsection of the input shaft and the oscillating shaft. The pin and sleevecan be slidably connected such that the pin and sleeve are free totranslate along each of their major axes. The pin can be connected tothe eccentric section of the input shaft by a bearing or bushing suchthat the pin cannot translate radially away from the second centralaxis. The pin can be rigidly coupled to the oscillating shaft such thatthe pin cannot move radially with respect to the third central axis. Thesleeve can be connected to the eccentric section of the input shaft by abearing or bushing such that it cannot translate radially away from thesecond central axis. The sleeve can be directly connected to theoscillating shaft such that it cannot translate radially away from thesecond central axis. In some embodiments, input shaft is parallel to theoscillating shaft.

In some embodiments, the oscillator includes a cutting tool coupled tothe oscillating shaft. In some embodiments, the input shaft includes acounter weight to balance to rotation of the eccentric section about thefirst central axis. In some embodiments, the oscillator includes abearing disposed around the input shaft. In some embodiments, theoscillator includes a bearing disposed around the oscillating shaft. Insome embodiments, the oscillator includes a collet formed at a distalend of the oscillating shaft, the collet including a plurality of armsextending distally around a central axis of the oscillating shaft.

In some embodiments, the oscillator includes a retainer having a centrallumen, where the retainer is slidably disposed around the plurality ofarms of the collet. In some embodiments, the oscillator includes arelease actuator configured to translate the retainer relative to theplurality of arms of the collet. In some embodiments, a proximal surfaceof the retainer extends at an oblique angle to the central axis of theoscillating shaft, where the release actuator is configured to translatein a direction perpendicular to the central axis of the oscillatingshaft and includes a surface that abuts the proximal surface of theretainer.

Another example embodiment of the present disclosure is a surgicalinstrument, including a housing, an elongated sleeve extending from thehousing, an input configured to receive continuous rotational motion, anoutput configured to couple to an end effector extending through thesleeve beyond a distal end thereof, and an oscillator configured toconvert the continuous rotational motion of the input into oscillatingmotion of the output. The instrument can include an end effector releasewith an actuator to operate the end effector release, the end effectorrelease being configured to selectively couple and decouple the endeffector to the output. In some embodiments, the end effector releasecomprises a collet. In some embodiments, the end effector is a blade. Insome embodiments, the blade is crescentic.

In some embodiments, the oscillator input further comprises an inputshaft having an eccentric section defining a central axis that is offsetfrom a rotational axis of the shaft, the output includes an output shaftoffset from the input shaft, and a linkage is disposed around theeccentric section of the input shaft at a first end thereof and coupledto the output shaft at a second end thereof to oscillate the outputshaft in response to rotation of the input shaft. In some embodiments,the linkage is coupled to the output shaft by the second end of thelinkage being slidably received within a bore of the output shaft. Insome embodiments, the linkage is coupled to the output shaft by a pinextending through a lumen formed in the second end of the linkage, wherethe pin extends parallel to and is offset from a central axis of theoutput shaft.

In some embodiments, the instrument includes a frame slidably coupled tothe housing. In some embodiments, the frame is coupled to a handleconfigured to be grasped by a user. In some embodiments, the handleextends parallel to a longitudinal axis of the instrument. In someembodiments, the handle extends transversely to a longitudinal axis ofthe instrument.

In some embodiments, the instrument includes a trigger configured tocontrol translation of the housing relative to the frame. The triggercan translate relative to the frame along an axis parallel to alongitudinal axis of the instrument. The trigger can translate relativeto the frame along an axis transverse to a longitudinal axis of theinstrument. In some embodiments, the trigger pivots relative to theframe along an axis perpendicular to a longitudinal axis of theinstrument. In some embodiments, frame is coupled to a second sleevethat receives the elongate sleeve within a lumen thereof. In someembodiments, the second sleeve has an opening formed at a distal endthereof to permit the end effector to extend beyond the distal end ofthe second sleeve.

In some embodiments, the instrument includes an actuator to controlcoupling of the second sleeve to the frame. In some embodiments, theinstrument includes a biasing element to resist distal translation ofthe housing relative to the frame.

Any of the features or variations described above can be applied to anyparticular aspect or embodiment of the present disclosure in a number ofdifferent combinations. The absence of explicit recitation of anyparticular combination is due solely to the avoidance of repetition inthis summary.

BRIEF DESCRIPTION OF DRAWINGS

This disclosure will be more fully understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is an illustration of one embodiment of a bone and tissueresection device according to the present disclosure;

FIG. 2 is an illustration of the stationary and drive assemblies of thebone and tissue resection device of FIG. 1;

FIG. 3A is an illustration of another embodiment of a bone and tissueresection device according to the present disclosure;

FIG. 3B is an illustration of the stationary assembly of the bone andtissue resection device of FIG. 3A;

FIG. 3C is an illustration of the drive assembly of the bone and tissueresection device of FIG. 3A;

FIG. 3D is an illustration of the distal end of the drive assembly ofFIG. 3C with a blade attached;

FIGS. 4A-4C are illustrations of one embodiment of a distal end of adrive assembly with a blade according to the present disclosure;

FIG. 5 is an illustration of another embodiment of a distal end of adrive assembly with a blade according to the present disclosure;

FIGS. 6A and 6B are illustrations of yet another embodiment of a distalend of a drive assembly with a blade according to the presentdisclosure;

FIGS. 7A-7C are illustrations of one embodiment of a bone and tissueresection device having a pivoting trigger configured to actuate themovement of the drive assembly;

FIG. 8 is an illustration of another embodiment of a bone and tissueresection device having an alternative grip and trigger arrangement;

FIGS. 9A-9G are illustrations of embodiments of a bone and tissueresection device having a rack and pinion arrangement between thestationary assembly and the drive assembly;

FIGS. 10A-10E are illustrations of different embodiments of engagementsystems for removably coupling a drive assembly to a stationaryassembly;

FIGS. 11A-11C are illustrations of one embodiment of a bone and tissueresection device having a longitudinally extending handle and triggerarrangement;

FIGS. 12A-12H are illustrations of one embodiment of a drive assemblyhaving a piston oscillator;

FIGS. 13A-13F are illustrations of one embodiment of a drive assemblyhaving a four bar linkage oscillator;

FIG. 14 is an illustration of one embodiment of a bone and tissueresection device having an alternative axial grip arrangement that isintegral to the oscillator;

FIG. 15 is an illustration of one embodiment of a bone and tissueresection device having yet another alternative axial grip arrangementthat is detachable from the oscillator;

FIG. 16 is an illustration of one embodiment of a bone and tissueresection device having a thumb-actuated trigger;

FIGS. 17A and 17B are illustrations of one embodiment of a bone andtissue resection device having a coring saw blade that rotates in asingle direction;

FIG. 18 is an illustration of one embodiment of a counter-rotating bladedevice for use with an oscillating drive assembly;

FIGS. 19A and 19B are illustrations of one embodiment of a bone andtissue resection device with a depth adjustment mechanism for adjustingthe position of a cutting edge by translating a drive mechanism.

FIGS. 20A and 20B are illustrations of one embodiment of a bone andtissue resection device with a depth adjustment mechanism configured toadjust the axial position of the cutting edge with respect to the shieldwithout adjusting the axial position of the drive mechanism

FIGS. 21A and 21B are illustrations of one embodiment of a bone andtissue resection device with a depth adjustment mechanism that includeshandle configured to be operated by a user to apply a force to advance acutting edge; and

FIGS. 22A and 22B are illustrations of one embodiment of a bone andtissue resection device with a powered depth adjustment mechanismoperable to adjust the position of a cutting edge.

DETAILED DESCRIPTION

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the devices and methods disclosed herein. One ormore examples of these embodiments are illustrated in the accompanyingdrawings. Those skilled in the art will understand that the devices andmethods specifically described herein and illustrated in theaccompanying drawings are non-limiting exemplary embodiments and thatthe scope of the present disclosure is defined solely by the claims. Thefeatures illustrated or described in connection with one exemplaryembodiment may be combined with the features of other embodiments. Suchmodifications and variations are intended to be included within thescope of the present disclosure.

Additionally, to the extent that linear or circular dimensions are usedin the description of the disclosed devices and methods, such dimensionsare not intended to limit the types of shapes that can be used inconjunction with such devices and methods. A person skilled in the artwill recognize that an equivalent to such linear and circular dimensionscan easily be determined for any geometric shape. Further, in thepresent disclosure, like-numbered components of the embodimentsgenerally have similar features. Still further, sizes and shapes of thedevices, and the components thereof, can depend at least on the anatomyof the subject in which the devices will be used, the size and shape ofcomponents with which the devices will be used, and the methods andprocedures in which the devices will be used.

Example Powered Cutting Systems

FIG. 1 is an illustration of one embodiment of a bone and tissueresection device according to aspects of the embodiments disclosedherein. FIG. 1 shows a bone and tissue resection device 10 that includesa stationary assembly 200 and a drive assembly 100 slidably coupled withthe stationary assembly 200. The drive assembly 100 includes a housing101 that is coupled with a motor 20 (e.g., a source of continuousrotational motion) and a thumb trigger 190 positioned to allow a user toslide the drive assembly in the distal (D) direction with respect to thestationary assembly 200. The stationary assembly 200 includes a frame201 that is slidably engaged with the housing 101 of the drive assemblyand a handle 290 sized and shaped to allow a user's fingers and/or palmhold onto the handle 290 of the stationary assembly 200 while the user'sthumb actuates the thumb trigger 190 of the drive assembly 190. Thestationary assembly 200 includes a spring 270 positioned in the frame201. The spring 270 is positioned to bias the drive assembly 100 in aproximal (P) direction against the force of the user against the thumbtrigger 190, thus maintaining the normally open position of the cuttingregion 250. In some embodiments, the spring 270 is positioned to biasthe oscillator 100 distally inside the stationary assembly 200 such thatthe cutting region 250 is normally closed. Actuating the oscillator 100in this configuration forces the cutting region 250 open and releasingthe trigger 190 would cause the spring 270 to provide a constant forceon the blade until it closes and makes the cut in the cutting region250.

The stationary assembly 200 includes a shield assembly 220 that extendsfrom the frame 201 to a footplate 222 at the distal end. In someembodiments, the shield assembly 220 is integrated with the stationaryassembly. FIG. 1 shows a shield assembly 220 that is coupled to a distalend of the frame 201 of the stationary assembly 200 with a clip 228. Theshield assembly 220 includes an elongated sleeve 221 that extendsdistally from the frame 201 to a cutting region 250 where there is awindow opening along the shield assembly 220 from a distal end of theelongated sleeve 221 to the footplate at the distal end of the shieldassembly 220. The shield assembly 220 is configured to protect a blade(not visible) that is coupled to the drive assembly 100.

In operation, the drive assembly 100 transfers energy to the blade fromthe motor (e.g., causes the blade to oscillate or rotate inside theshield assembly 220) and actuation of the thumb trigger 190 (e.g., aforce applied in the distal direction by a user holding the handle 290)slides the drive assembly 100 distally against the bias force of thespring 270. The distal movement of the drive assembly causes the bladeto pass through the cutting region 250. Tissue or bone present in thecutting region 250 is contacted and resected by the blade as it passesthough. In some embodiments, the blade is a crescentic blade thatoscillates at a high frequency with a small angular deviation. In someembodiments, the blade is abrasive and will be less effective at cuttingsoft tissue than it will bone thus improving safety.

FIG. 2 is an illustration of the stationary and drive assemblies of thebone and tissue resection device of FIG. 1. FIG. 2 show the stationaryassembly 200 and drive assembly 100 with the handle 290 of thestationary assembly detached from the frame 201 of the stationaryassembly. In some embodiments, the handle 290 is integrated with theframe 201. FIG. 2 shows the frame 201 includes an interface 209 forsecuring a separate handle 290 to the stationary assembly 200. Theshield assembly 220 is attached to the frame 201 of the stationaryassembly 220 with a clip 228 that engages with a distal channel 227formed in the frame 201. The cutting region 250 of the shield assembly220 includes two support members 223 that connect the foot plate 222 tothe distal end of the elongated sleeve 221. Also visible is a blade tipof a blade 300 disposed inside the shield assembly 220 and attached tothe drive assembly via a blade shaft (not visible). The drive assembly100 includes a button actuator 181 extending through the housing 101 forreleasing the blade shaft from being coupled with the drive mechanisminside the housing 101. The proximal end of the drive assembly 100includes a coupling mechanism 182 for attaching the motor 20 to thedrive mechanism. When coupled, continuous rotational motion from themotor 20 is delivered to a drive mechanism inside the housing 101 of thedrive assembly 100. Additionally, FIG. 2 shows the frame 201 of thestationary assembly includes a latch 261 that can prevent the driveassembly 100 from decoupling with the frame 201 when in the firstillustrated position (e.g., via a protrusion 262 that interferes withproximal motion of the drive assembly 100 relative to the frame 201) andcan be moved to a second position (e.g., by rotating a proximal end ofthe latch 261 in the direction of arrow 263) to allow decoupling of thedrive assembly 100 from the frame 201 (e.g., by withdrawing the driveassembly 100 proximally with respect to the frame 201).

FIG. 3D is an illustration of how in operation, a disposable blade 300can be attached to the drive assembly 100 while the drive assembly isseparated from the stationary assembly 200 and a disposable shieldassembly 220 is attached to the stationary assembly. Afterwards, thedistal end of the blade 300 can be inserted into the shield assembly 220and slid distally until the drive assembly 100 is engaged with thestationary assembly 200 and retained by the latch 261. In this position,the drive assembly can be biased proximally against the latch 261 by thespring 270, which positions the distal tip of the blade 300 at theproximal end of the cutting region 250. When a user presses on the thumbtrigger 190 in the distal direction, the drive assembly moves againstthe bias force of the spring 270 to drive the blade 300 through thecutting region to conduct a cutting operation.

FIG. 3A is an illustration of another embodiment of a bone and tissueresection device 10 according to aspects of the embodiments disclosedherein. FIG. 3A shows a bone and tissue resection device 10 with adifferent handle 390 attached to the frame 201 of the stationaryassembly 200. FIG. 3A shows the motor 20 is coupled to an externalcontroller or power source via a line 22 connected to the motor 20 withan articulating coupling 21. FIG. 3A also shows that the blade 300 is acrescentic blade that is configured to be oscillated by an oscillatormechanism of the drive assembly 100. The crescentic blade can span thewidth of the two support beams 223 of the shield assembly 220 such thatthe cutting region 250 (e.g., the path of the blade 300) is an arc fromone support beam 223 to the other support beam 223 across the width ofthe shield assembly 220 that extends from a distal end of the elongatedsleeve 221 (e.g., where the distal end of the blade 300 is first exposedas it is move distally by the drive assembly) to the foot plate 222. Insome embodiments, the cutting region 250 does not extend all the way tothe foot plate 222 to prevent the blade 300 contacting the footplate222. The blade 300 extends inside the support beams 223 but, in someembodiments, and as shown, has a crescentic or generally arcuate shapethat forms the cutting region above the support beams 223, but notbelow, such that there is a window 224 extending between the supportbeams 223 opposite the blade 300. The window 224 can allow a user orimaging device to observe the cutting region 250 and blade 300 as itcontacts and resects tissue. The open window configuration thus enablesthe blade 300 to be viewed from both sides (e.g., directly from above inthe orientation of the figure and through the window 224 from below inthe orientation of the figure) as it passes through the cutting region250. This can be advantageous because, in use, a resection device suchas a burr or Kerrison Rongeur is often positioned against bone or tissuein a manner that obstructs direct visualization of the blade 300 fromabove in the orientation of the figure. Therefore, in prior deviceswithout any window 224, a surgeon or other user can be forced to performfinal positioning for a resection cut without being able to see theblade directly.

In some embodiments, the an oscillator mechanism of the drive assembly100 includes a mechanical arrangement configured to convert continuousrotational motion from a motor, which may be, for example, an internalmotor or an external motor 20 attached to the drive assembly, into anoscillating movement for oscillating the blade 300. In some embodiments,the oscillator comprises a piezoelectric mechanism for oscillating theblade 300 at ultrasonic frequencies. In some embodiments, the oscillatoroscillates the blade 300 around the proximal-distal axis of the blade300. In other embodiments, the oscillator oscillates the blade 300axially along proximal-distal axis of the blade 300. In otherembodiments, the oscillator oscillates the blade 300 axially alongproximal-distal axis of the blade 300 and around the proximal-distalaxis of the blade 300.

FIG. 3B is an illustration of the stationary assembly 200 of the boneand tissue resection device 10 of FIG. 3A. FIG. 3B shows the frame 201of the stationary assembly 200 with the drive assembly 100 removed ornot yet inserted. The handle 390 is shown attached to the interface 209of the frame 201 via a plurality of screws 399. The handle 390 includesa first gripping portion 391 and a second gripping portion 392, both onthe distal face of the handle 390. The second gripping portion 392 issized and shaped to be engaged by the index finger of a user's hand thatis grasping the handle 390, and the first gripping portion 391 is sizedand shaped to be engaged by one or more of the user's remaining fingers.

The frame 201 is shown to have a generally C-shaped cross-section thatdefines a channel 260 that accepts the exterior of the housing 101 driveassembly 100. The channel 260 includes rail features 262 along thechannel 260. The rail features 262 permit the housing 101 to slide alonga single axis of translation (e.g., along the proximal and distaldirections). In some embodiments, the frame 201 can completelyencapsulate the drive assembly 100 instead of just being a C-shapedcross-section. In these circumstances, the guide protrusions on thedrive assembly 106 and mating rail feature on the frame 262 are nolonger necessary but can still be used to constrain movement. The distalend of the frame 201 includes an opening 221′ that is sized to acceptthe blade 300 when the drive assembly 100 is inserted into thestationary assembly 200. The distal end of the frame 201 also provides asurface to be engaged by the spring 270 for biasing the drive assembly100 in the proximal direction. The distal end of the frame 201 alsoincludes channels 227 for securing the clip 228 of the disposable shieldassembly 220 to the stationary assembly 200. The proximal end of theframe 201 includes a latch 261 for retaining the drive assembly in thechannel 260 of the frame 201. In operation, the drive assembly 100 isslid into the channel 260 and engaged with the rail features 262, andthen the drive assembly slides distally along the path defined by therail features 262 until secured by the latch 261, which prevents thedrive assembly 100 from being removed (e.g., moved in the proximaldirection to disengage from the rail features 262). To decouple thecomponents, a user can toggle the latch 262 (e.g., as described above)to release the drive assembly 100 and retract the drive assembly 100proximally to decouple the drive assembly 100 from the stationaryassembly 200.

FIG. 3C is an illustration of the drive assembly 100 of the bone andtissue resection device 10 of FIG. 3A. FIG. 3C shows the drive assembly100 separate from the stationary assembly 200. In some embodiments, thedrive assembly 100 is configured to be used as a free-hand resectiondevice without being coupled with a stationary assembly 200. In FIG. 3C,a blade shaft shield 120 is shown extending distally from the housing101. The blade shaft shield 120 is configured to protect and constrainthe blade shaft between the exit of the housing 101 and the blade 300positioned at the distal end of the blade shaft (as shown in FIG. 3D).In operation, a proximal end of the blade shaft can be inserted at anopening 122 in the distal tip 121 of the blade shaft shield 120 and theblade shaft can be slid proximally until it engages with a drivemechanism inside the housing 101. In some embodiments, the user canfirst press the button actuator 181 to enable the blade shaft to beengaged with the drive mechanism. In other embodiments, the buttonactuator 181 may only need to be depressed to release the blade from thedrive mechanism and an applied insertion force to the blade shaft canengage the coupling mechanism without actuation of the button actuator181 (e.g., via a one-way latch, such as those commonly used on doors,etc.).

FIG. 3C shows the housing 101 of the drive assembly having guideprotrusions 106 extending from the housing. The guide protrusions 106are configured to engage with the rail features 262 of the frame 201 ofthe stationary assembly 200, as shown in FIG. 3B. The distal end of thehousing 101 includes a protrusion 102 that engages the spring 270 of thestationary assembly 100. FIG. 3D is an illustration of the distal end ofthe drive assembly 101 of FIG. 3C with a blade 300 attached. FIG. 3Dshows the crescentic blade 300 with a blade shaft 310 extendingproximally from the blade 300 into the blade shaft shield 120. In theillustrated position, the blade 300 is fully inserted into the bladeshaft shield 120 and a proximal end of the blade shaft 310 is coupledwith the drive mechanism inside the housing 101. The blade 300 is freeto oscillate or rotate about the major axis of the blade shaft 310,depending on the type of drive mechanism that is in the housing 101. Insome embodiments, the blade can be a circular blade or a coring blade.In operation, a user can free-hand use the drive assembly in thisconfiguration. It should also be noted that a user could change betweenusing the drive assembly free-hand and in connection with a stationary,as well as perhaps using different blade types in each configuration,multiple times during a procedure.

Further, while the above-described embodiments illustrate configurationsin which movement of the drive assembly 100 with respect to thestationary assembly 200 is manually actuated, in other embodiments abone and tissue resection device 10 can include a powered actuator formoving the drive assembly 100 with respect to the stationary assembly200. In such embodiments, a user of the bone and tissue resection device10 can electrically or mechanically control the powered actuator to movethe drive assembly 100 and thereby move the blade 300 in the cuttingregion 250.

Example Crescentic Blade Cutting Assemblies

FIGS. 4A-4C are illustrations of an embodiment of a distal end of adevice according to aspects of the embodiments disclose herein, such asthe device 10 described above. FIG. 4A shows a first embodiment of acutting assembly 400 that includes the disposable shield 220 and theblade 300. The cutting assembly 400 defines a cutting region 250 betweena closed footplate 420 at the distal end and an opening 229 of thedistal end of the elongated sleeve 221 of the shield assembly 220. Theclosed footplate 420 can be coupled to the shield assembly 220 by asingle support beam 430 that spans a length of the cutting region 250.In some embodiments, the support beam 430 can be split into multiplesupport beams to allow for visualization of the cutting area. Thesupport beam 430 can be sized and shaped to be inside of the path of theblade 300 as it transits the cutting region 250. In some embodiments,and as shown, the blade 300 can be a crescentic blade that surrounds thesupport beam 230. In some embodiments, a cutting tip 301 of the blade300 cuts toward the closed footplate 420 but stops short of contactingthe footplate due to a feature on the blade that abuts a correspondingfeature on the shield 220 in order to prevent teeth of the cutting tip301 from contacting the footplate 420 directly. In other embodiments,contact between the blade and footplate can be controlled in other ways,including by designing the length of longitudinal translation of theblade to make contact impossible, etc. In some embodiments, the blade300 comprises a cutting tip 301 with any of a variety of toothed designsor a diamond grit blade, etc. In some embodiments, and as shown in moredetail in FIG. 6B, the shield assembly 220 can include a featureattached to the support beam 430 that rests on or against an insidediameter of the crescentic blade to wipe off the inner diameter of theblade upon retraction of the blade proximally relative to the featureafter a cut is made.

In operation, a drive assembly 100, to which the blade 300 is attached,can be moved distally with respect to a stationary assembly 200, towhich the shield assembly 220 is attached, and this relative motionbetween the blade 300 and the shield assembly 220 can move the blade 300though the cutting region 250. With the blade 300 being rotated or, asillustrated, oscillated, by a drive mechanism in the drive assembly 100,any tissue or bone present in the cutting region 250 can be contacted bythe cutting tip 301 of the blade 300 and resected. In some embodiments,bone or tissue disposed in the cutting region 250 can be prevented frommoving out of the path of the blade 300 contacting a proximal surface ofthe footplate 422.

The proximal surface of the footplate 422 can include a crescentictrough region 421 that forms an outer lip 422 and an inner lip 423. Theouter lip 422 can extend to an outer peripheral edge 424 of thefootplate such that the outer lip 422 can define a sharpness that is afunction of the width of outer lip 422 at the peripheral edge 424 andthe angle of the trough 421 as it approaches the peripheral edge 424. Inoperation, the cutting tip 301 of the blade 300 can approach the troughof the foot plate 421 and the outer lip 422 can engage with an outeredge of the cutting tip 301 in an overlapping jaw-like fashion, suchthat the fully extended position of the blade 300 locates the cuttingtip 301 distally equal to or beyond the position of the outer lip 422(while still allowing some separation between the blade tip 301 and thesurface of the trough region 421). In some embodiments, the cutting tip301 does not extend distally to the outer lip 422, but close enough toeffectively cut tissue or bone therebetween. Similarly, the inner lip423 engages with an inner edge of the cutting tip 301, such that thefully extended position of the blade 300 locates the cutting tip 301distally equal to or beyond the position of the inner lip 423. In someembodiments, and as shown, the support beam 430 has a generally flatinner-facing surface and an outer edge 431 that has a width less than acorresponding inner cord section of the blade 300 to allow the blade topass distally across the support beam 430. In some embodiments, thisinner facing surface 432 is cupped or has an opening to increase theamount of material that is in the opening for resection.

FIG. 4B shows the full length of the elongated sleeve 221, from theopening 229 at the distal end to a proximal end configured to attach tothe stationary assembly 200. Inside the elongated sleeve 221 is theblade shaft 310, showing the proximal edge extending beyond theelongated sleeve 221 to be coupled with the drive assembly 100 toactuate (e.g., oscillate) the blade 300. In operation, when the driveassembly 100 is moved distally, the blade shaft 310 is moved distallyinto the elongated sleeve 221 of the shield assembly 220. FIG. 4C showsthe arrangement of the blade 300 around the support beam 430. In someembodiments, the proximal end 439 of the support beam 430 can beconfigured to abut a distal face of a proximal end of the blade (e.g.,the opposite side of face 390 of FIG. 3A) when the blade reaches adesigned maximum distal extension through the cutting region 250. Thisarrangement can prevent the cutting tip 301 of the blade 300 fromcontacting the footplate 420 by having the distal face of the bladecontact the proximal end 439 of the support beam 430 before the cuttingtip 301 contacts the footplate 420 and prevent further distaltranslation of the blade 300.

FIG. 5 is an illustration of another cutting assembly 500 according toaspects of the embodiments disclose herein. FIG. 5 shows the cuttingassembly 500 includes the shield assembly 220 with an elongated tube 221surrounding a blade 300 and a footplate 520 at a distal end of theshield assembly 220. The footplate 520 is connected to the distal end ofthe elongated tube 221 by two support beams 530. In some embodiments,the cutting assembly 500 includes only one support beam 530, however theuse of two support beams can increase rigidity of the assembly andbetter resist deflection during use, etc. In some embodiments, a platecovers the opening created by the support beam(s) 530 to encapsulate thecutting region 250 allowing for tissue extraction after resection. Theblade 300 can be nested inside the support beams 530 and configured toextend though the cutting region (indicated by arrow 250) during acutting operation. The footplate 520 can include an outer lip 521 thatextends to the peripheral edge 522 of the footplate to engage with thecutting tip 301 of the blade 300 as discussed above with respect to FIG.4A. The footplate 520 can be totally closed or partially open. Forexample, an open footplate is shown in FIGS. 17A and 17B (e.g., opendistal end 1722). The outer diameter of the support beams 530 are thesame diameter as the elongated tube 221 in this embodiment.

In FIG. 5, the support beams 530 include an inner surface having a ridge536 that marks a location where the support beam 530 transitions from afirst sidewall thickness 535 to a second sidewall thickness 537 that isgreater than the first thickness. More particularly, the support beam530 can extend radially inward to achieve the second thickness 537 atpoints below the maximum angular reach of the oscillating blade 300 inorder to add strength and stiffness to the support beams 530. Above theridge 536, the support beam 530 can maintain the first sidewallthickness 536 that is configured to conform to or accommodate the outerdiameter of the blade 300 as it passes through the cutting region 530.The support beams 530 rigidly locate the footplate 520 to enable theblade 300 to deliver a force to the tissue or bone in the cutting region250 by pressing the tissue or bone against the footplate as the bladeadvances toward the footplate. Preventing deflection of the footplate520 can enable the blade 300 to deliver a larger force to the tissue orbone and more successfully resect tissue.

FIGS. 6A and 6B are illustrations of another embodiment of a cuttingassembly 600 for use with a drive assembly 100 and stationary assembly200 according to aspects of the embodiments disclosed herein. FIG. 6Ashows a cutting assembly 600 that includes a shield assembly 220 and afootplate 620 connected to the distal end of the elongated sleeve 221 ofthe shield assembly 220 by two support beams 630. The support beams caninclude opposing inner faces 636 that are configured to allow the blade300 to pass inside and along the inner faces 636 as the blade 300 movesthrough the cutting region 250. The support beams 630 can have athickness 635 to provide the support beams 620 sufficient stiffness andstrength to rigidly locate the footplate 620 with respect to the blade300 during a cutting operation where the blade drives bone, for example,against the footplate 620 as the cutting tip 301 is advanced into thebone. The footplate 620 also includes a lip 621 that extends to aperipheral edge 622 of the footplate 620, similar to the embodimentsdescribed above. In some embodiments, the footplate can include an innercurved surface that curves proximally from a proximal face 623 of thefootplate to the lip 621. The curved inner surface can be configured toallow the cutting tip 301 to move distally past the lip 621 withoutcontacting proximal face 623 to improve the cutting action of thecutting tip 301. The outer diameter of the support beams 630 can belarger than the elongated tube 221, as shown in this embodiment.

FIG. 6B shows the cutting assembly 600 with the blade 300 removed toshow that the cutting assembly includes a cleaning plate 225 in theopening 229 at the distal end of the elongated sleeve 221. The cleaningplate 225 and sidewall of the sleeve 221 define a crescentic opening 226that the blade 300 passes through to enter the cutting region 250. Thecleaning plate 225 therefor runs along the inner surface of the blade300 and, as the blade is retracted proximally into the elongated sleeve221, for example by the biasing force of the spring 270 moving the driveassembly proximally, the cleaning plate 225 can remove any resectedtissue or debris attached to the blade 300 after a cutting strokethrough the cutting region 250. In some embodiments, the improvedcutting action of the oscillating blade 300 can cleanly resect a mass oftissue without pulverizing, fragmenting, or otherwise breaking it intoseveral smaller pieces. In such embodiments, the cleaning plate 225 canserve to retain the resected mass of tissue between the cleaning plateand the footplate 620 as the blade 300 is retracted proximally. Agrasping surgical instrument can then be used to remove the resectedmass (e.g., through the window 624) and clear the cutting region 250 foranother use. In other embodiments, the resected mass can be clearedusing a suction instrument rather than a grasper, while in still otherembodiments the instrument can simply be positioned for another use andmovement of new tissue into the cutting region 624 can eject theresected tissue mass through the window 624. The outer diameter of thesupport beams 630 can be larger than the elongated tube 221, as shown inthis embodiment.

In some embodiments, any of the various cutting assemblies or distal endassemblies described above can include one or more sensors to aid inpositioning the instrument at a surgical site. For example, one or moresensors can be positioned along the footplate, blade, shield sleeve, orsupport arms to detect proximity to one or more anatomical structures,such as nerves, blood vessels, etc. Any of a variety of known sensorscan be employed, including optical sensors, electromagnetic sensors(e.g., electrodes), pressure sensors, etc. Such sensors can be disposedalong an exterior surface of the device or integrated into the device.In addition, embodiments formed from materials not readily visible in aparticular type of medical imaging, e.g., fluoroscopy, etc. can includeone or more markers attached thereto or embedded throughout made from amaterial visible with such imaging.

Example Drive Assembly Actuation

The following figures illustrate different configurations for theactuation of the drive assembly 100 with respect to the stationaryassembly 200.

FIGS. 7A-7C are illustrations of one embodiment of a bone and tissueresection device 700 having a pivoting trigger 730 configured to actuatethe movement of the drive assembly 100. FIG. 7A illustrates a bone andtissue resection device 700 having a stationary assembly 702 with apistol grip handle 729 connected to a frame 720 and a pivoting trigger730 configured pivot about an axis 733 and push the drive assembly 100distally.

In operation, the pivoting trigger 730 can be moved (indicated by arrow799) from an extended position 731 b until a lever arm 732 of thepivoting trigger 730 contacts the drive assembly 100 (e.g., at aproximal lip 734, see FIG. 7C) directly or indirectly so that pullingthe pivoting trigger 730 further advances the drive assembly 100 and theblade shaft shield 120 distally against the biasing force of a spring270. The movement 799 can drive the blade (not shown, e.g., blade 300described above) into the cutting region 250 in the shield assembly 220.The pivoting trigger 730 can be moved to a fully retracted position 731a where the drive assembly 100 is advanced distally as far as possible.In some embodiments, a stop mechanism in the shield assembly 220 cancontact the blade 300 to prevent further distal movement of the driveassembly. A sliding or stationary stop block 728 can also prevent thetrigger from overextending in the “locked” position (as shown). Slidingthe stop block 728 to the “unlocked” position (indicated by arrow 797)can push the pivoting trigger 730 out of contact with the drive assembly100, allowing the drive assembly 100 to be removed or inserted into thehousing 720 of the stationary assembly 702. After inserting the driveassembly 100 into the stationary assembly 720, pulling the pivotingtrigger 730 can push the stop block 728 back into the “locked” position.A spring 729 can be mounted in the frame 720 and can push on the driveassembly, taking up tolerances and reducing rattle between moving parts,for example, the drive assembly 101 and the frame 720. FIG. 7B is aperspective view of the bone and tissue resection device 700. FIG. 7C isa detail view of the bone and tissue resection device 700, where thestationary assembly 702 is translucent, showing the engagement of thepivoting trigger 730 with the drive assembly 100.

FIG. 8 is an illustration of another embodiment of a bone and tissueresection device 800 having an alternative grip and trigger arrangement.In particular, the embodiment of FIG. 8 includes a proximal handle 829attached to the drive assembly 100 and a trigger 830 attached to a frame820 of a stationary assembly 802. In operation, the handle 829 andtrigger 830 can be squeezed together by a user's hand, thereby advancingthe drive assembly 100 distally (e.g., against biasing force from spring270 not visible in FIG. 8) to advance the blade 300 within the cuttingregion 250 toward the footplate 222. FIG. 8 shows the handle 829 andtrigger 830 in their fully compressed position, wherein the blade 300 isadvanced distally through the cutting region 250. Releasing thecompression between handle 829 and trigger 830 from this position canallow a biasing force (e.g., from spring 270 not visible in FIG. 8) towithdraw the drive assembly 100 proximally with respect to the frame 820and trigger 830, thereby withdrawing the blade 300 proximally throughthe cutting region and into the shield assembly 220.

FIG. 9A-9D are illustrations of one embodiment of a bone and tissueresection device 900 having a rack and pinion that control movementbetween a stationary assembly 902 and a drive assembly 100. FIG. 9Ashows a stationary assembly 902 that includes a frame 920 having ahandle 929 and a trigger 930 that is slidably coupled to the frame 920.The trigger 930 can translate or slide proximally and distally withregard to the handle 929. An opposing rack-and-pinion mechanism 960 isconfigured to move the drive assembly 100 distally when pulling thetrigger 930 proximally toward the handle 929 by interaction of one rack963 on the trigger 930, one rack 160 on the drive assembly 100, and apinion or gear 961 positioned between them and rotatably mounted to theframe 920, as shown in more detail in FIG. 9B. In some embodiments, twopinions 961, 961′ can be utilized and can be spring-loaded or otherwisebiased toward one other to engage two angled racks, as shown in moredetail in FIGS. 9C and 9D. Biasing the pinions 961, 961′ in this mannercan help maximizes engagement with the racks and takes up tolerances,thereby reducing rattle between the various moving parts in the device900.

FIG. 9B shows the rack and pinion mechanism 960 between the trigger 930and the drive assembly 100 in greater detail. The stationary assembly902 can include a spring 927 biasing the trigger 930 away from thehandle 929. The rack and pinion mechanism 960 can include a bottom rack963 on the trigger positioned below the housing 101 of the driveassembly, a top rack 160 on the housing 101 of the drive assembly 100positioned above the bottom rack 963, and a pinion 961 positionedbetween the top rack 160 and the bottom rack 963. In operation, thetrigger 930 can be driven proximally (as indicated by arrow 998) by thefingers of a user's hand squeezing together the handle 929 and trigger930. As the trigger 930 translates proximally relative to the handle929, the rack 963 also translates proximally. The pinion 961, which iscoupled to the frame 920, rotates and causes the rack 160 to translatethe drive assembly 100 distally (indicated by arrow 999). FIG. 9B alsoshows the drive assembly 100 secured in place by a latch mechanism 928,which is shown is more detail in FIGS. 10E and 10D.

FIG. 9C is a cross-sectional view of the bone and tissue resectiondevice 900 taken along the line A-A in FIG. 9B, showing one exemplarygeometry of a rack and pinion mechanism 960. FIG. 9C shows the bottomrack 963 and top rack 160 each comprising two parallel racks, with acorresponding set of opposed tapered pinions 961, 961′ between them. Asshown in FIG. 9D, the pinions 961 are spring-loaded to be biased towardseach other by springs 969. FIG. 9D shows two pinions 960 disposed alonga common axis 968 between the trigger 930 and the housing 101 of thedrive assembly 100. Each pinion 961 includes a spring 969 biasing thepinion 961 toward a midline of the device or toward the other pinion.The biasing force of the springs 969 (shown as arrows 990 a, 990 b) canapply an opposing force (shown as arrow 991) onto the trigger 930 andhousing 101. These opposing force 991 can urge the housing 101 upwardand the trigger 930 downward, which can press the guide protrusions 106of the housing 101 and the protrusions 970 of the handle 920 intocorresponding guide channels 262 and 970, respectively. By biasing theseelements together, tolerances can be taken up and rattle created by thedevice during operation (e.g., when the components are vibrating due tothe oscillating blade) can be minimized. These forces can also helpmaintain the coupling of the pinions 961, 961′ to the racks 160, 963.

FIG. 9E-9G are illustrations of another embodiment of a bone and tissueresection device 900′ having a handle 920′ and a trigger 930′ that fitsinto one or more grooves 931 formed therein that slide along one or morerails 970′ formed in a frame 920′ of the stationary assembly 902′. Thedevice 900′ can function similarly to the device 900 described above.FIG. 9F is a perspective view of the trigger 930′ and its relation tothe frame 920′. FIG. 9G is a cross-sectional view (taken along plane Bof FIG. 9E) showing the trigger 930′ coupled to the frame 920′ via apair of opposed protrusions or rails 970′ of the frame 930′.

FIGS. 10A-10E are illustrations of different embodiments of engagementsystems for removably coupling a drive assembly to a stationaryassembly. FIG. 10A shows a rack and pinion system for releasablycoupling a drive assembly 100 to a stationary assembly 902. The pinion961 can be capable of translation (indicated by arrow 1095) from afirst, locked position 1060, where the pinion 961 is engaged with thetop rack 106 of the housing 101 of the drive assembly, to a second,release position where the pinion 961 is disposed below the housing 101and clear of the rack 160 to enable the housing 101 to be inserted orremoved from the frame 920 of the stationary assembly 920. FIG. 10Bshows an alternative pinion release mechanism, where a straight pinion1061 can be translated laterally (as indicated by arrow 1097) todisengage from the rack 160, thereby freeing the top rack 160 andallowing the housing 101 to be decoupled from the frame 920. FIG. 10Cshows yet another embodiment of a pinion release mechanism, wherein apinion 1062 can be biased with a spring 1069 against the top rack 160 ofthe housing 101. To decouple the housing 101 from the stationaryassembly 920, a release button 1090 can be depressed (indicated by arrow1098) to translate the pinion 1062 laterally against the bias of thespring 1069. This translation can disengage the pinion 1062 from therack 160 and clear a path for the rack 160 (and housing 101 of the driveassembly) to be translated proximally for decoupling from the stationaryassembly 902.

FIG. 10D illustrates operation of one embodiment of the latch 928 shownin FIG. 9B that can selectively prevent decoupling of the housing 101relative to the frame 920. In operation, the housing 101 can betranslated distally relative to the frame 920 until a proximal endthereof, or another proximal-facing surface or other surface featurethereof, contacts the latch mechanism 928 and deflects latch mechanism928 laterally (in the direction of arrow 1099) to allow the housing 101to pass into the channel of the frame 920. Once the housing 101 isadvanced distally a sufficient amount, the latch 928 can move oppositethe arrow 1099 in FIG. 10D to the position shown in the perspective viewof FIG. 10D and the top view of FIG. 10E wherein a portion of the latch928 interferes with proximal translation of the housing 101 along thechannel in the frame 920 beyond the position of the latch. To decouplethe housing 101 from the frame 920, the latch 928 can be moved in thedirection of arrow 1099 until, for example, a channel 1098 formed in thelatch aligns with the channel of the frame 920 along which the housing101 translates. In some embodiments, and as shown in FIG. 10E, the latch928 can include a spring 1027 that is either separate from or built intothe latch 928 that biases the latch 928 in the locked position, as shownin FIGS. 10D and 10E, where the housing 101 is unable to move proximallyin the frame 920 past the latch 928.

Example Longitudinally Extending Trigger Configurations

FIGS. 11A-11C are illustrations of one embodiment of a bone and tissueresection device 1100 having a longitudinally extending handle andtrigger arrangement. Such embodiments include alternative handles forthe powered cutting systems disclosed herein wherein the handle ortrigger is arranged to extend longitudinally along the device. Theseembodiments can allow for pistol-grip or trigger-like actuation whileholding the device 1100 in a vertical or near-vertical orientationwithout the need to bend and twist the wrist and arm.

FIG. 11A shows the bone and tissue resection device 1100 having astationary assembly 1102 and a drive assembly 100 slidably coupled withthe stationary assembly 1102. The stationary assembly includes alongitudinally extending trigger 1129 positioned above the driveassembly 100 and a grip 1130 integrated into a frame 1120 disposedaround the drive assembly 100. In operation, and as shown in more detailin FIG. 11B, when the longitudinally extending trigger 1129 is movedtowards the grip 1130, a wedge integrated into the trigger 1129 cancontact a roller pin 1109 coupled to the drive assembly 100, therebyadvancing the drive assembly 100 distally.

FIGS. 11B and 11C illustrate the inside of the frame 1120 of thestationary assembly, where the wedge 1127 of the vertical trigger 1129is shown contacting the roller pin 1109 of an actuation sleeve 1108coupled to the drive assembly 100. In operation, when the trigger 1129moves towards the drive assembly 100 (as shown by arrow 1198 in FIG.11C), the roller pin 1109 is driven along the face 1128 of the wedge1127, thereby causing the sleeve 1108 and drive assembly 100 to advancedistally against the biasing force of the spring 270. As describedabove, this distal advancement of the drive assembly 100 also advancesthe blade 300 along the cutting region 250 to conduct a cutting strokeand resect tissue.

Example Oscillator Mechanisms

FIGS. 12A-12H are illustrations of a drive assembly having a pistonoscillator mechanism. FIG. 12A shows an oscillator drive assembly 1200having a housing 1201 that contains a piston oscillator mechanism, ablade shaft shield 120 extending distally from the housing 1201, aninput shaft 1230 to the piston oscillator mechanism extending proximallyfrom the housing 101, and a button release 181 for the blade shaft 310(not shown in FIG. 12A). The input shaft 1230 can include a couplingelement 1231 to be engaged by a corresponding element of a motor 20 toenable the motor 20 to spin the input shaft 1230. In operation, thepiston oscillator mechanism converts the input rotational motion of theinput shaft 1230 into an oscillating motion of an output shaft coupledto the blade shaft 310, as shown in FIGS. 12B-12H.

FIG. 12B shows the components of the oscillator drive assembly 1200without the housing 1201. The oscillator drive assembly 1210 includesthe input shaft 1230, an output shaft 1250, and a piston oscillatormechanism coupling the input shaft 1230 to the output shaft 1250, asexplained in more detail below. The input shaft 1230 can rotate freelyinside a plurality of bearings 1239, bushings, or directly against thehousing 1201 to secure the input shaft 1230 in the housing 1201. Theinput shaft 1230 includes a cylindrical eccentric section 1232 that hasa central axis B offset from, and parallel to, the central axis A of theinput shaft 1230 (see dl of FIG. 12E). The input shaft 1230 can alsoinclude a counterweight 1233 that counterbalances the eccentricallyrotating components coupled to the eccentric section 1232 to reduce orprevent excessive vibration from rotation of the input shaft.

The output shaft 1250 can also rotate freely inside a plurality ofbearings 1259, bushing, or directly against the housing 1201 to securethe output shaft 1250 in the housing 1201. The output shaft 1250 can bedirectly coupled to the blade shaft 310, or drive a blade coupling totransmit the oscillating torque to the blade shaft 310 indirectly. Thisembodiment includes a plurality of collet arms 1251 that define acentral recess to accept a proximal end of a blade shaft 310 (notshown). A retainer 1281 is slidably disposed around the collet arms 1251and configured to selectively lock the blade shaft (not shown) relativeto the output shaft 1250 as the retainer 1281 translates relative to theoutput shaft 1250 collapsing the collet arms 1251 towards the bladeshaft 310. The retainer 1281 can include an angled face 1283 that caninterface with a corresponding angled face 1284 of a wedge 1280extending towards the retainer. The wedge 1280 can be moved radiallytoward or away from the output shaft by actuation of the button release181. Accordingly, in use, a user can depress the button 181 (i.e., moveit in the upward direction of FIG. 12B) to advance the wedge 1284radially toward or away from the output shaft 1250. This movement of thewedge 1284 can cause the retainer 1281 to translate away from thewedging surface of the collet arms 1251. As the retainer 1281translates, it moves along a portion of the collet arms 1251 having atapered diameter such that the retainer exerts less compressive pressureon the collet arms 1251. In this state a user can insert or remove aproximal end of a blade shaft 310 due to the reduced grip of the colletarms 1251. Upon release of the button 181, the wedge 1280 can moveradially away from the output shaft 1250, resulting in the translationof the retainer 1281 towards the wedging surface of the collet arms 1251that can urge the collet arms 1251 against any blade shaft disposedtherebetween. This can lock the blade shaft, if present, to the outputshaft 1250.

Turning to the piston oscillator mechanism that couples the input shaft1230 to the output shaft 1250, FIG. 12B shows a connector 1240 disposedconcentrically around a bearing 1242 (see FIG. 12D) that is disposedaround the eccentric section 1232 of the input shaft 1230. The outputshaft 1250 has a stationary pin 1241 either integrated into the outputshaft 1250 or as a separate component extending therefrom into a bore1255 formed in the output shaft. In operation, rotation of the inputshaft 1230 can spin a central axis A (see FIG. 12E) of the eccentricsection 1232 about the central axis B (see FIG. 12E) of the input shaft1230, which is offset from the central axis of the eccentric section1232 by a distance di (see FIG. 12E). The eccentric rotation of theconnector 1240 driven by the eccentric section 1232 moves the connectorover the pin 1241 with respect to a central axis C of the output shaft1250 (see FIG. 12B) in a manner similar to a piston connector rod beingmoved up and down by a crankshaft in an internal combustion engine. Asthe input shaft 1230 rotates, the angular position of the central axis Bof the eccentric section 1232 of the input shaft moves relative to thecentral axis C of the output shaft 1250 creating an oscillation aboutthe central axis C. Repeated rotations of the input shaft 1230 thereforecause repeated oscillating movement of the output shaft 1250 about itscentral axis C. The range of the oscillating motion is shown in moredetail in FIGS. 12G and 12H, which provide an end-view of the shafts1230, 1250 and connector 1240. In some embodiments, the pin 1241 can beintegral to the connector 1240, and the output shaft 1250 will feature abore for the pin 1241 to move within to create the oscillation.

FIG. 12C shows a detail view of the input shaft 1230, output shaft 1250,connector 1240, and spacer 1258. Note that in the perspectives of eachof FIGS. 12B and 12C, the input shaft is rotationally orientated suchthat the central axis B of the input shaft 1230 (see FIG. 12E) isaligned with the central axis A of the eccentric section 1232 (see FIG.12E). FIG. 12D is a perspective view of the components shown in FIG.12C. Visible in the perspective view is the bearing 1242 disposed insidethe connector 1240 that allows the eccentric section 1232 to spin insidethe connector 1240. In some cases, the bearing 1242 can be a bushing, orthe connector can be directly contacting the eccentric section 1232.FIG. 12D also shows the pin 1241 extending from the bore 1255 in theoutput shaft 1250. In some embodiments, and as shown, the bore 1255 is ahole through the output shaft 1250 that is orthogonal to the outputshaft's axis of rotation C. FIG. 12F is a detail view without the spacer1258.

FIGS. 12G and 12H illustrate the conversion of rotational motion of theinput shaft 1230 into oscillating motion of the output shaft 1250. FIGS.12G and 12H each show the piston oscillator mechanism in a vieworthogonal to the central axes B, C of the input shaft 1230 and theoutput shaft 1250, respectively. Horizontal (H) and vertical (V) axesare labeled in both figures (though these terms are relative, asrotating the instrument can reorient which axis is vertical vs.horizontal), and the intersection of the horizontal and vertical axes isplaced at the central axis of rotation B of the input shaft 1230. Alsoshown in the figure is the central axis A of the eccentric section 1232.The intersection of the vertical axis with a second horizontal axis 1299is the central axis C of the output shaft 1250. In operation, the inputshaft 1230 spins, clockwise or counterclockwise, and the output shaft1250 oscillates clockwise and counterclockwise between the positionsshown in FIG. 12G and FIG. 12H. The difference between these positionstherefore represents the range of oscillation of the output shaft 1250.

In FIG. 12G, the eccentric section 1232 is maximally extended in a firsthorizontal direction (e.g., to the left with respect to FIG. 12G) andthe pin 1241 has rotated the output shaft 1250 clockwise by an anglerepresented by the angular relation of a reference line 1281 withrespect to the second horizontal axis 1299. The reference line 1281 ischosen to be perpendicular with the second horizontal axis 1299 when theeccentric section 1232 is maximally extended in either verticaldirection (e.g., up or down with respect to FIG. 12G). The angulardifference between line 1299 and 1281 in FIG. 12G is a maximum clockwisethe rotation of the output shaft 1250 induced by the rotation of theeccentric section 1232 about which the connector 1240 is disposed.

FIG. 12H illustrates the eccentric section 1232 maximally extended in asecond horizontal direction (e.g., to the right with respect to FIG.12G) opposite the first direction shown in FIG. 12G. In FIG. 12H, thepin 1241 has rotated the output shaft 1250 counterclockwise by an anglerepresented by the angular relation of the reference line 1281 withrespect to the second horizontal axis 1299. The angular differencebetween line 1299 and 1281 in FIG. 12H is maximum counterclockwise therotation of the output shaft 1250 induced by the rotation of theeccentric section 1232 about which the connector 1240 is disposed.

The angular range of oscillation shown in FIGS. 12G and 12H can beadjusted by, for example, adjusting various geometric parameters of theassembly. For example, adjusting the eccentric section to increase ordecrease the distance di between the central axis B of the input shaft1230 and the central axis A of the eccentric section 1232 can adjust theangular range of oscillation. Similarly, adjusting a distance betweeninput and output shafts 1230, 1250, respectively, can influence theangular range of oscillation. Generally speaking, the above-describedconfiguration can be well suited to applications that require a smallerangular range of oscillation at a higher rate of oscillation. By way ofexample only, the total angular range of oscillation shown in FIGS. 12Gand 12H can be less than about 10° in some embodiments. In someembodiments, the total angular range can be about 7°.

The piston oscillator mechanism of FIGS. 12A-12H has a number ofadvantages over known oscillators. For example, the piston oscillatormechanism can convert high input RPMs (revolutions per minute) into highoutput OPMs (oscillations per minute) due to low friction and backlashgenerated during the movements of the piston oscillator mechanism. Forexample, the input shaft 1230 can be counter balanced such that rotationof the connector 1240 and pin 1241 generate minimal vibration, and themovement of the pin 1241 in the bore 1255 is the only point of contactbetween moving parts outside of the bearings. In some embodiments, thepin and/or the bore 1255 can be made formed of, or coated with, amaterial having low friction, or the pin 1241 and/or the bore 1255 canbe lubricated to further reduce friction. Further, in some embodiments,the bore 1255 can be lined with a sleeve or insert that can aid inreducing frictional forces. Exemplary rotation and oscillation rates canbe quite high, e.g., as high as about 80,000 OPM in some embodiments.Operating at such high oscillation rates can enable superior cuttingperformance from the blade 300 or other instrument coupled to the outputshaft 1250.

FIGS. 13A-13F are illustrations of an oscillator drive assembly 1300having a four bar linkage oscillator. FIG. 13A shows the oscillatordrive assembly 1300 with a housing 1301 that contains that an inputshaft 1330, an output shaft 1350, and a four bar linkage oscillator thatconnects the input shaft 1330 to the output shaft 1350. The input shaft1330 extends proximally from the housing 1301 of the drive assembly 1300with a coupling element 1331 that can be engaged by a correspondingelement of a motor 20 (not shown) to enable the motor 20 to spin theinput shaft 1330. The output shaft 1350 can be configured to couple witha blade shaft 310 (not shown) such that oscillations of the output shaft1350 are transferred to the blade shaft 310. The four-bar linkageoscillator can couple an offset or eccentric section of the continuouslyspinning input shaft 1330 to the output shaft 1350 by means of a linkage1340. The input shaft 1330 can be rotatably secured in the housing 1301by bearings 1339, bushings, or directly contacting the housing and caninclude an eccentric section 1332 with a counterweight 1333. Further,the output shaft 1350 can include collet arms 1355 disposed at a distalend thereof, as well as a translating retainer 1304 that can selectivelylock a blade or other instrument shaft between the collet arms 1355 in amanner similar to the retainer 1281 described above. In someembodiments, the output shaft 1350 can be directly coupled to the bladeshaft 310. In some embodiments, the output shaft 1350 can be indirectlycoupled to the blade shaft 310 through means of a temporary mechanical,or magnetic connection. In some embodiments, the offset pin 1341 can bedirectly coupled to, or part of the blade shaft 310 to minimizereciprocating mass.

FIGS. 13B and 13C show the moving components of the four-bar linkageoscillator drive assembly 1300 without the housing 1301, bearings 1339,bushings 1302, 1303, or retainer 1304. In operation, the output shaft1350 oscillates as the central axis of the eccentric section 1332 movesclose to and then away from the central axis of the output shaft 1350.The linkage 1340 is connected to the eccentric section 1332 by a bearing1342, bushing, or direct contact to the eccentric section 1332 at oneend and to an offset pin 1341 coupled to the output shaft 1350 at anopposite end of the linkage 1340 by a bearing, bushing, or directcontact. In some embodiments, the offset pin 1341 is part of the linkage1340 and travels inside a bearing, bushing, or direct contact offsetfrom the central axis of the output shaft 1350.

FIGS. 13D-13F show the motion of the four bar linkage oscillator 1310 asit converts the clockwise rotational motion of the input shaft 1330(arrows 1390) to oscillating motion of the output shaft 1350 (arrows1394, 1396). In FIGS. 13D-13F, the intersections of the first horizontal(H1) axis with the vertical (V) axis (as noted above, horizontal andvertical are relative terms depending on an orientation of the device)represent the central axis of rotation B of the input shaft 1330, andthe intersections of the second horizontal axis (H2) with the vertical(V) axis represent the central axis of rotation C of the output shaft1350. In FIG. 13D, the eccentric section 1332 is minimally extended inthe vertical direction away from the output shaft 1350 (in other words,the central axis A of the eccentric section 1332 is rotated to aposition where it is disposed a maximum distance away from the outputshaft 1350), which represents a near maximum oscillation of the outputshaft 1350 in the counterclockwise direction (as indicated by arrow1394). This oscillation is represented by an angular deviation of areference line 1398 through the center of output shaft 1350 that ischosen such that the reference line 1398 aligns with the vertical axis Vbetween the maximum and minimum oscillation points, as shown in FIG.13E. As FIG. 13D represents the near maximum counterclockwiseoscillation of the output shaft 1350, continued clockwise rotation 1390of the input shaft 1330 eventually moves the eccentric section 1332vertically towards the output shaft 1350, which rotates the offset pin1341 and the output shaft 1350 clockwise about the central axis C of theoutput shaft 1350, as shown in FIG. 13E.

FIG. 13E represent about 90 degrees of clockwise rotation 1390 of theeccentric section 1332 from the position of FIG. 13D. Continued rotationof the input shaft 1330 rotates the eccentric section to a near maximumvertical position, as shown in FIG. 13F, where a central axis A of theeccentric shaft 1332 is closest to the output shaft 1350 and the linkage1340 has been driven upwards (in the plane of FIG. 13F). This motion ofthe linkage 1340 can rotate the input shaft 1350 clockwise to a maximumoscillation in the clockwise direction (as indicated by arrow 1396).Continued rotation of the input shaft 1330 rotates the eccentric shaft1332 to move the linkage 1340 away from the output shaft 1350 andinduces counterclockwise rotation in the output shaft 1350. Therefore,as the input shaft 1330 spins, the output shaft 1350 oscillates betweenthe positions shown in FIGS. 13D and 13F. The ratios between thedistances between the pivot points can change the amplitude of thisoscillation (e.g., changing the offset distance between the central axisof the input shaft 1330 and eccentric section 1332, the length of thelinkage 1340, the offset of the pin 1341, etc.).

The four bar linkage oscillator can also provide advantages over knownoscillators. For example, in comparison to a traditional Scotch yoke thefour bar linkage oscillator lacks a bearing that slaps between sides ofa yoke, which can fatigue the yoke and radially impact a bearing on theoffset shaft. Thus, in traditional Scotch yoke, as the RPM/OPM increasesthe likelihood for fatigue of the yoke and bearing wear on the offsetshaft increases. The four bar linkage oscillator, in contrast, has onlyrotational bearing surfaces that remain in contact at all times,allowing for improved durability and more predictable wear. In someembodiments, the linkage 1340 can be made of a bearing grade material,thereby negating the need for a separate bearing between the linkage1340 and either of the offset pin 1341 and/or the eccentric section 1332of the input shaft 1330.

In comparison to the piston oscillator described above, the four barlinkage can in some embodiments be configured to provide a greaterangular range of oscillation, but may not be capable of operating at thevery high speeds achievable with the piston oscillator. For example, insome embodiments the range of angular oscillation for the four barlinkage oscillator can be up to about 40°. In the illustratedembodiment, the range of angular oscillation can be about 31°.

In some embodiments, the output shaft 1250 or 1350 or blade shaft 310can also be forced to oscillate axially about their axis of rotation inorder to improve debris clearing during the cutting operation. Thisaxial motion can be created through use of a cam mechanism to drive theoutput shaft 1250 or 1350 or blade shaft 310 proximally and distallyduring the course of a single stroke.

Alternative Configurations

FIG. 14 is an illustration of one embodiment of a bone and tissueresection device having an alternative longitudinally extending griparrangement. FIG. 14 shows the bone and tissue resection device 1400includes a drive assembly 100 and a stationary frame 1420 around thedrive assembly 100 and a disposable shield assembly 220 temporarilyattached to the stationary frame 1420. The stationary frame 1420includes an attachment beam 1428 for connecting a coupling element 1401of the shield assembly 220 and preventing rotation of the shieldassembly 220 with respect to the stationary frame 1420. The couplingelement 1401 includes a clip feature at one end thereof that engageswith the attachment beam 1428 by being rotated around the shieldassembly 220. The stationary frame 1420 has a grip 1429 disposed aroundthe stationary frame 1420 and shaped to allow a user to grasp thestationary frame 1420 in their hand, with their thumb resting againstthe thumb trigger 190 of the drive assembly 100. In some embodiments,the stationary frame 1420 is connected to the oscillator assembly 100and cannot be removed from the oscillator assembly 100. In someembodiments, the stationary frame 1420 can be separated from theoscillator assembly 100 allowing the user to handle the oscillatorassembly 100 directly. In some embodiments, a spring can be used toretract the blade 300 inside of the disposable shield assembly 220.

FIG. 15 is an illustration of a bone and tissue resection device havingyet another alternative longitudinally extending grip arrangement. Thebone and tissue resection device 1500 includes a drive assembly 100 anda stationary frame 1520 around the drive assembly 100 and a disposableshield assembly 220 attached to the stationary frame 1520. Thestationary frame 1420 includes a coupling 1528 for connecting the shieldassembly 220. In some embodiments, the shield assembly 220 is integralto the stationary frame 1520. The stationary frame 1520 has a grip 1529disposed around the stationary frame 1520 and shaped to allow a user tograsp the stationary frame 1520 in their hand, with their thumb restingagainst the thumb trigger 190 of the drive assembly 100. The stationaryframe 1520 includes a spring 270 that biases the drive assembly 100 inthe proximal direction and against, for example, the user's forceagainst the thumb trigger 190 to move the drive assembly 100 in thedistal direction and translate the blade 300 through the cutting region250 at the distal end of the shield assembly 220.

FIG. 16 is an illustration of a bone and tissue resection device havinga thumb-actuated trigger. The bone and tissue resection device 1600includes a stationary assembly 1620 and a drive assembly 100 slidablyengaged directly or indirectly with a frame 1621 of the stationaryassembly 1620. A shield assembly 220 is attached to the stationaryassembly with an offset elongated arm 1601 that engages with a coupler1628 on the frame 1621 to retain the shield assembly 220 in place. Theelongated arm 1601 extends radially from the shield assembly to increasethe ability of the coupler 1628 to prevent rotation of the elongatedtube 221 of the shield assembly if any rotational energy is transferredto the footplate 222 during use. In some embodiments, a spring can beused to retract the blade 300 inside of the disposable shield assembly220.

The frame 1621 of the stationary assembly includes an integrated handle1629 shaped to be grasped by a user's hand, with their thumb against thethumb trigger 190 of the drive assembly 100 to actuate the movement ofthe drive assembly 100 with respect to the frame 1621. In someembodiments the shape fills the palm to enable the user to guide thefootplate 222 with their hand but leaves the thumb free to advance theoscillator assembly 100. Here, the frame 1621 surrounds the thumbtrigger 190 such depressing the thumb trigger distally to move the driveassembly 100 advances the thumb trigger 190 toward the stationaryassembly 1620. In some embodiments, the thumb trigger 190 being recessedinto the frame 1621 can further secure the position of the user's thumbagainst the thumb trigger 190 and prevent a user's finger from beingpinched or trapped between the trigger 190 and the stationary housing1620. In some embodiments, the bone and tissue resection device 1600 caninclude a powered actuation mechanism to move the drive assembly 100,and the thumb trigger 190 can be a button that the user engages tocontrol the powered actuation mechanism to move the drive assembly 100distally or proximally. In some embodiments, the powered actuationmechanism can move the drive assembly 100 proximally when the thumbtrigger 190 is released.

In some embodiments the feature a user presses to advance the blade 300towards the footplate 222 to cut can activate the motor that causes theoscillator assembly 100 to oscillate.

Coring Saw Device Examples

FIGS. 17A and 17B are illustrations of a bone and tissue resectiondevice 1700 having a rotating coring saw blade 1731. A continuouslyspinning coring saw can be nested inside a housing with an opening toallow the blade to be exposed to the tissue to be cut. FIG. 17A shows ashield sleeve 1721 fixedly attached to a handle 1791 and a driveassembly 1710 slidably attached to the handle 1791. The drive assembly1710 can be configured to be coupled with a motor 20 and a coring blade1731. The drive assembly 1710 can include a thumb trigger 1790 forpushing the drive assembly 1710 distally using the thumb of a user'shand that is holding the handle 1791. The shield sleeve 1721 can includean open distal end 1722 and one or more cutting region(s) 250 throughwhich the coring blade 1731 passes as it is driven distally by the driveassembly being advanced with respect to the shield sleeve 1721. FIG. 17Bshows the bone and tissue resection device 1700 with the blade 1731attached. While shown with an open distal end 1722, in some embodimentsthe shield sleeve 1721 can have a closed end. In some embodiments, theshield sleeve 1721 can be detached from the handle to allow for avariety of shield options to be used. In some embodiments, the driveassembly 1710 can be advanced through means of a manual squeeze styletrigger or automated through use of an actuator to drive the motionforward and backward. In some embodiments, the drive assembly 1710 canhave a spring to return the blade 1731 to the starting position.

Counter-Rotating Blade Examples

FIG. 18 is an illustration of a counter-rotating blade device 1800 foruse with an oscillating drive assembly, such as the drive assembly 100of FIG. 1. FIG. 18 shows the counter-rotating blade device 1800 includesa distal end with dual counter rotating blades 1821, 1822 with eithertoothed or diamond grit ends 1831, 1832. The counter-rotating bladedevice 1800 includes a coupling mechanism 1938 at a proximal end forcoupling the counter-rotating blade device 1800 with the output of anoscillating drive assembly. In operation, counter rotation stabilizesthe blades 1821, 1822 to ensure maximum cutting efficiency. In someembodiments, the counter rotation of the blades 1821, 1822 can be driventhrough use of a planetary gear mechanism 1811 attached to the couplingmechanism 1838. In some embodiments, the counter rotation of the blades1821, 1822 can be driven through two separate oscillating mechanisms.

Alternative Depth Adjustment Mechanism Arrangements

FIGS. 19A and 19B are illustrations of one embodiment of a bone andtissue resection device 1900 with a depth adjustment mechanism 1901 foradjusting the position of a blade 300 by translating a drive assembly100. The bone and tissue resection device 1900 includes a stationaryassembly 200 with a shield assembly 220 extending to a cutting region250 proximal to a footplate 420 at the distal end of the shield assembly220. The bone and tissue resection device 1900 also includes a driveassembly 100 configured to move with respect to the stationary assembly200, the drive assembly 100 including a blade shaft 310 extendingdistally from the drive assembly 100 to a blade 300 through a bladeshaft shield 120. The depth adjustment mechanism 1901 is configured tomove the drive assembly 100 along a proximal-distal axis of the bone andtissue resection device 1900, whereby the movement of the drive assembly100 causes the blade 300 to move through the cutting region 250 at thedistal end of the shield assembly 220. FIG. 19A shows the bone andtissue resection device 1900 with the drive assembly 100 in a proximalposition with the blade 300 retracted from the cutting region 250. InFIG. 19B, the depth adjustment mechanism 1901 has moved the driveassembly 1901 distally until the blade 300 has crossed the entirecutting region 250.

FIGS. 20A and 20B are illustrations of one embodiment of a bone andtissue resection device 2000 with a depth adjustment mechanism 2001 isconfigured to adjust the axial position of the blade 300 with respect tothe cutting region 250 without adjusting the axial position of the drivemechanism 100. The depth adjustment mechanism 2001 is configured to movethe blade 300 and blade shaft 310 with respect to the drive assembly 100along a proximal-distal axis of the bone and tissue resection device3000, whereby the depth adjustment mechanism 2001 causes the blade 300to move into and out of the cutting region 250 at the distal end of theshield assembly 220. FIG. 20A shows the bone and tissue resection device2000 with the blade 300 and blade shaft 310 in a proximal position withthe blade 300 retracted from the cutting region 250. In FIG. 20B, thedepth adjustment mechanism 2001 has moved the blade 300 distally untilthe blade 300 has crossed the entire cutting region 250.

FIGS. 21A and 21B are illustrations of one embodiment of a bone andtissue resection device 2100 with a depth adjustment mechanism 2102 thatincludes handle 2101 configured to be operated by a user to apply aforce to advance a blade 300 through a cutting region 250. In operation,as shown in FIG. 22A, the depth adjustment mechanism 2102 can, forexample pivot about a point 2103 in the bone and tissue resection device2100 such that the force applied to the handle 2101 by the user in aservers to rotate the handle 2101 about the pivot point 2103, as shownby arrow 2104. In rotation, the handle 2101 drive the depth adjustmentmechanism 2102 distally against the drive assembly 100, which moves theblade 300 through the cutting region 250, as shown in FIG. 22B. In otherembodiments, the drive assembly 100 is stationary depth adjustmentmechanism 2102 is configured to drive the blade 300 through the cuttingregion 250 and the blade 300 and the blade shaft 310 move with respectto the drive assembly 100.

FIGS. 22A and 22B are illustrations of one embodiment of a bone andtissue resection device 2200 with a powered depth adjustment mechanism2201 operable to adjust the position of a blade 300 with respect to acutting region 250. The bone and tissue resection device 2200 includes atrigger 2202 configured to be operable by a user holding the bone andtissue resection device 2200. The trigger 2202 is configured to send asignal via a control wire 2203 to the depth adjustment mechanism 2201.FIG. 22A shows the depth adjustment mechanism 2201 is coupled to thedrive assembly 100 in order to move the drive assembly 100 along aproximal-distal axis and thereby move the blade 300 into and out of thecutting region 250. In some embodiments, the depth adjustment mechanism2201 can move the drive assembly 100 distally when a user engages thetrigger 2202 and then move the drive mechanism 100 proximally when theuser releases the trigger 2202. In other embodiments, the trigger 2202can be configured to be operable in more than one direction, such thatthe user can actively control both the distal and proximal movement ofthe blade 300 in the cutting region 250. In some embodiments, the depthadjustment mechanism 2201 includes an electric motor. In someembodiments, the drive assembly 100 is not driven by the depthadjustment mechanism 2201, and instead the depth adjustment mechanism2201 moves the blade 300 with respect to the drive assembly 100.

It should be noted that any ordering of method steps expressed orimplied in the description above or in the accompanying drawings is notto be construed as limiting the disclosed methods to performing thesteps in that order. Rather, the various steps of each of the methodsdisclosed herein can be performed in any of a variety of sequences. Inaddition, as the described methods are merely exemplary embodiments,various other methods that include additional steps or include fewersteps are also within the scope of the present disclosure.

The instruments disclosed herein can be constructed from any of avariety of known materials. Exemplary materials include those which aresuitable for use in surgical applications, including metals such asstainless steel, titanium, nickel, cobalt-chromium, or alloys andcombinations thereof, polymers such as PEEK, ceramics, carbon fiber, andso forth. The various components of the instruments disclosed herein canhave varying degrees of rigidity or flexibility, as appropriate fortheir use. Device sizes can also vary greatly, depending on the intendeduse and surgical site anatomy. Furthermore, particular components can beformed from a different material than other components. One or morecomponents or portions of the instrument can be formed from a radiopaquematerial to facilitate visualization under fluoroscopy and other imagingtechniques, or from a radiolucent material so as not to interfere withvisualization of other structures. Exemplary radiolucent materialsinclude carbon fiber and high-strength polymers.

The devices and methods disclosed herein can be used inminimally-invasive surgery and/or open surgery. While the devices andmethods disclosed herein are generally described in the context ofspinal surgery on a human patient, it will be appreciated that themethods and devices disclosed herein can be used in any of a variety ofsurgical procedures with any human or animal subject, or in non-surgicalprocedures.

The devices disclosed herein can be designed to be disposed of after asingle use, or they can be designed to be used multiple times. In eithercase, however, the device can be reconditioned for reuse after at leastone use. Reconditioning can include any combination of the steps ofdisassembly of the device, followed by cleaning or replacement ofparticular pieces, and subsequent reassembly. In particular, the devicecan be disassembled, and any number of the particular pieces or parts ofthe device can be selectively replaced or removed in any combination.Upon cleaning and/or replacement of particular parts, the device can bereassembled for subsequent use either at a reconditioning facility, orby a surgical team immediately prior to a surgical procedure. Thoseskilled in the art will appreciate that reconditioning of a device canutilize a variety of techniques for disassembly, cleaning/replacement,and reassembly. Use of such techniques, and the resulting reconditioneddevice, are all within the scope of the present application.

The devices described herein can be processed before use in a surgicalprocedure. First, a new or used instrument can be obtained and, ifnecessary, cleaned. The instrument can then be sterilized. In onesterilization technique, the instrument can be placed in a closed andsealed container, such as a plastic or TYVEK bag. The container and itscontents can then be placed in a field of radiation that can penetratethe container, such as gamma radiation, x-rays, or high-energyelectrons. The radiation can kill bacteria on the instrument and in thecontainer. The sterilized instrument can then be stored in the sterilecontainer. The sealed container can keep the instrument sterile until itis opened in the medical facility. Other forms of sterilization known inthe art are also possible. This can include beta or other forms ofradiation, ethylene oxide, steam, or a liquid bath (e.g., cold soak).Certain forms of sterilization may be better suited to use withdifferent portions of the device due to the materials utilized, thepresence of electrical components, etc.

One skilled in the art will appreciate further features and advantagesof the disclosure based on the above-described embodiments. Accordingly,the disclosure is not to be limited by what has been particularly shownand described. All publications and references cited herein areexpressly incorporated herein by reference in their entirety.

What is claimed is:
 1. An oscillator for converting continuousrotational motion into oscillating motion, comprising: an input shaftconfigured to continuously rotate about a first central axis, a portionof a length of the input shaft defining an eccentric section, theeccentric section defining a second central axis that is offset from thefirst central axis; a connector rotatably coupled around the eccentricsection; an oscillating shaft offset from the input shaft and configuredto rotate about a third central axis; and a pin coupled to theoscillating shaft and extending towards the connector, wherein theconnector comprises a sleeve slidably receiving an end of the pin,wherein continuous rotation of the input shaft about the first centralaxis causes an eccentric movement of the connector, and the eccentricmovement of the connector oscillates the sleeve along the pin andoscillates the pin with respect to the oscillating shaft, therebyoscillating the oscillating shaft about the third central axis, andwherein the pin is connected to the eccentric section of the input shaftby a bearing or bushing such that the pin cannot translate radially awayfrom the second central axis.
 2. The oscillator of claim 1, wherein thepin and sleeve extend perpendicular to the axis of the eccentric sectionof the input shaft and the oscillating shaft.
 3. The oscillator of claim1, wherein the pin and sleeve are slidably connected such that the pinand sleeve are free to translate along each of their major axes.
 4. Theoscillator of claim 1, wherein the pin is rigidly coupled to theoscillating shaft such that the pin cannot move radially with respect tothe third central axis.
 5. The oscillator of claim 1, wherein the sleeveis connected to the eccentric section of the input shaft by a bearing orbushing such that it cannot translate radially away from the secondcentral axis.
 6. The oscillator of claim 1, wherein the sleeve isdirectly connected to the oscillating shaft such that it cannottranslate radially away from the second central axis.
 7. The oscillatorof claim 1, wherein the input shaft is parallel to the oscillatingshaft.
 8. The oscillator of claim 1, further comprising a cutting toolcoupled to the oscillating shaft.
 9. The oscillator of claim 1, whereinthe input shaft further comprises a counter weight configured to balancerotation of the eccentric section about the first central axis.
 10. Theoscillator of claim 1, further comprising a bearing disposed around theinput shaft.
 11. The oscillator of claim 1, further comprising a bearingdisposed around the oscillating shaft.
 12. The oscillator of claim 1,further comprising a collet formed at a distal end of the oscillatingshaft, the collet including a plurality of arms extending distallyaround a central axis of the oscillating shaft.
 13. The oscillator ofclaim 12, further comprising a retainer having a central lumen; whereinthe retainer is slidably disposed around the plurality of arms of thecollet.
 14. The oscillator of claim 13, further comprising a releaseactuator configured to translate the retainer relative to the pluralityof arms of the collet.
 15. The oscillator of claim 14, wherein aproximal surface of the retainer extends at an oblique angle to thecentral axis of the oscillating shaft; wherein the release actuator isconfigured to translate in a direction perpendicular to the central axisof the oscillating shaft and includes a surface that abuts the proximalsurface of the retainer.
 16. An oscillator for converting continuousrotational motion into oscillating motion, comprising: an input shaftconfigured to continuously rotate about a first central axis, a portionof a length of the input shaft defining an eccentric section, theeccentric section defining a second central axis that is offset from thefirst central axis; a connector rotatably coupled around the eccentricsection; an oscillating shaft offset from the input shaft and configuredto rotate about a third central axis; and a pin coupled to theoscillating shaft and extending towards the connector, wherein theconnector comprises a sleeve slidably receiving an end of the pin,wherein continuous rotation of the input shaft about the first centralaxis causes an eccentric movement of the connector, and the eccentricmovement of the connector oscillates the sleeve along the pin andoscillates the pin with respect to the oscillating shaft, therebyoscillating the oscillating shaft about the third central axis, andwherein the sleeve is connected to the eccentric section of the inputshaft by a bearing or bushing such that it cannot translate radiallyaway from the second central axis.
 17. The oscillator of claim 16,wherein the input shaft further comprises a counter weight configured tobalance rotation of the eccentric section about the first central axis.18. An oscillator for converting continuous rotational motion intooscillating motion, comprising: an input shaft configured tocontinuously rotate about a first central axis, a portion of a length ofthe input shaft defining an eccentric section, the eccentric sectiondefining a second central axis that is offset from the first centralaxis; a connector rotatably coupled around the eccentric section; anoscillating shaft offset from the input shaft and configured to rotateabout a third central axis; and a pin coupled to the oscillating shaftand extending towards the connector, wherein the connector comprises asleeve slidably receiving an end of the pin, wherein continuous rotationof the input shaft about the first central axis causes an eccentricmovement of the connector, and the eccentric movement of the connectoroscillates the sleeve along the pin and oscillates the pin with respectto the oscillating shaft, thereby oscillating the oscillating shaftabout the third central axis and wherein the input shaft furthercomprises a counter weight configured to balance rotation of theeccentric section about the first central axis.
 19. The oscillator ofclaim 18, wherein the pin is rigidly coupled to the oscillating shaftsuch that the pin cannot move radially with respect to the third centralaxis.